112 SCIENCE OF SUCCESSFUL THRESHING. 



lower short bull-pinion shaft has no leather between it and 

 the main frame; however, it can be set deeper in gear at 

 any time by turning its set-screw from below. The main 

 spur-wheel shaft is not adjustable and the set screws bear- 

 ing against its boxes are used only to prevent them from 

 becoming loose in their slots. Adjustable slides are placed 

 above and below the bull-wheel. Those below have set- 

 screw adjustment, and should be adjusted, as they wear, so 

 that the bull- wheel just clears the lower bull-pinions. The 

 top slides prevent the up and down movement of the bull- 

 wheel, and should be set down as they wear. The traverse- 

 rollers prevent the bull-wheel from crowding endwise on the 

 bull-pinions. They should be set out by the key adjustment 

 as they wear. The spur-pinion frame is secured by four 

 five-eighths inch bolts in slotted holes. These allow adjust- 

 ment of the pinion so that it may be made to mesh properly 

 with the spur-wheel. When properly set, the pitch circles 

 will touch and the spur-pinion shaft will be parallel with the 

 spur-wheel shaft. 



Caution Concerning the Bull-Pinion Boxes. The bull- 

 pinion boxes, 8ij4W and 8i^W, have flanges which hook 

 over the outside of the main frame, thus preventing them 

 from crowding toward the center. When these boxes have 

 been removed, care must be taken in replacing them to insure 

 these flanges hooking over the outside of the frame, for if 

 they be placed too far toward the center of the power, these 

 flanges may come in contact with the box seat and prevent 



